Shutaro Karube
Altermagnetism is a new class of magnetism proposed by Šmejkal et al [1, 2] realizing spin splitting at Fermi energy, even though in an antiferromagnet due to specific crystal structure, leading to generation of spin current with spin polarization depending on Néel vector interestingly. This is called spin-splitter effect (SSE) [3] to generate novel spin current.
Our group has observed the unconventional generation of the spin current in an altermagnetic RuO2(101) with all -, - and -polarized spins depending on crystal orientation (applied current direction) by means of spin-torque ferromagnetic resonance in an adjacent NiFe alloy layer at room temperature [4]. This feature in the view point of Néel vector dependent polarization is in good agreement with the proposed theory of the SSE [1-3].
Furthermore, we have also realized field-free magnetization switching in a neighbor perpendicular- magnetized Co layer using -polarized spin current driven by the SSE in the RuO2 [4]. Thus, we experimentally observed the SSE and demonstrated the utility for spintronic application.
In this special workshop, I would like to show you further detail of the actual experiments regarding the SSE originated from the altermagnetism.
[1] L. Šmejkal et al, Phys. Rev. X 12, 031042 (2022).[2] L. Šmejkal et al, Phys. Rev. X 12, 040501 (2022).
[3] R. González-Hernández et al, Phys. Rev. Lett. 126, 127701 (2021). [3] S. Karube et al, Phys. Rev. Lett. 129, 137201 (2022).